We have all become more conscious of the importance of indoor air quality (IAQ). The hvac industry's emphasis on IAQ has spurred numerous articles on Sick Building Syndrome and building-related illnesses; most of these cite inadequate ventilation as the primary cause. However, simply using conventional system design to boost the ventilation rates (to a minimum of 15 cfm/person as prescribed in ASHRAE Standard 62-1989), often leads to unacceptable indoor humidity levels and high operating costs.
To handle the higher quantities of ventilation air with the conventional system, the designer typically increases the equipment's cooling and heating capacity. Although the higher energy bills are undesirable, an even greater problem is humidity control, primarily during the cooling season.